Solar car park puts students in the shade

A university car park in south-east Queensland is making itself twice as useful to the academic community after its conversion to a 1.1MW solar plant.

Let’s face it, car parks are pretty ho-hum. They take up a lot of space and not much really happens in them. The anxiety of looping around a full car park brings on a panic and the joy of finding a spot only lasts a moment. But until driverless cars announce their arrival with a digital “toot” we’re stuck with car parks, so how could they be made a bit more useful?

By turning them into solar farms, of course.

It’s a solution that has become a bit of a specialty of Autonomous Energy. The Sydney-based company has completed a 1.1MW project on the University of Southern Queensland’s Toowoomba campus, where about 3,800 solar PV panels cover an area equivalent to about four football fields, enough for 449 cars.

It’s part a $6 million, 2MW rollout that will include rooftop installations at three other USQ campuses. The institution hopes its carbon emissions of 16,000 tonnes a year will be cut by 20%, where purchased electricity accounts for about 88% of emissions, it says.

“It’s a long way from installing solar panels on a roof, put it that way,” says Autonomous Energy managing director Mark Gadd. “It’s much more complicated, a lot more technically engrossed, a lot more stakeholders and a lot more risk.”

At the USQ project the energy generated by the panels is sent through 19 SMA 60kW three-phase string inverters into a 1,250kVA GE transformer which steps the voltage up before connecting to the university’s 11kV network.

A custom-designed 1,600-amp AC solar protection board with a campus-wide high-voltage zero export control future proofs the campus, Gadd says, allowing USQ to install additional solar PV capacity at Toowoomba using the same zero export control system and still meeting Ergon Energy’s requirements.

The high-voltage protection system communicates to the inverter management equipment so the inverter output can ramp down as required to ensure zero exports to the network.

About 135 tonnes of steel was used in the framework, with vehicles allowed 2.6m of clearance. At Sydney Market the solar canopy is high enough off the ground to accommodate trucks. “It just depends on the application,” he says.

When it’s dark, 165 LED fittings brighten things up for students as they make their way to their cars after a hard day of being lectured.

Autonomous Energy has done this work before, with a 920kW solar car park at Sydney Markets and plans to build one atop a 14-storey car park at Sydney Airport.

The effects of coastal wind on a structure 14 floors up is vastly different from what is felt on the top of a typical residence, he says. “A lot of rigorous engineering goes into it.” Framework to support the panels needs to be custom designed and engineered, he says.

In high-rise car parks, one particular challenge is lining up the loads of the shading structure with the supporting columns underneath, without losing car park spaces. “No shopping centre manager is going to want to lose a car parking space,” Gadd says. “They put a high price on it.”

At the Sydney Markets project the water captured on the arrays is put to good use instead of being sent into a stormwater drain, Gadd says. “Compared to having an uncovered car park it adds a lot more value and you’re turning what is otherwise a very dead, boring, lifeless place into a solar power station.”

At USQ, it isn’t just about counting the energy and savings that come off the panels, however. Solar car parks also look cool.

“Compared to shade sails you see on the roofs of some car parks [a solar array] looks a lot more impressive and futuristic,” Gadd says. “They look great.”

Toowoomba-based Jinko Solar regional sales manager Thomas Bywater reckons car park solar shading makes all sorts of sense. “It brings solar down into the space where people are living and breathing rather than keeping it secret on the rooftop,” he says. “At the same time, our future leaders are walking among the panels and surely their impression of solar is therefore more concrete and familiar.”

Bywater is hopeful the USQ job – which uses Jinko’s 285-watt monocrystalline PERC modules – will inspire similar projects across the manufacturing and agricultural businesses in the Darling Downs region of South-East Queensland.